Answer:
D.
Step-by-step explanation:
Set this up as a ratio with #parts of tank on top and #minutes on the bottom and then solve it as a proportion with x being the unknown number of minutes in the second ratio.
Notice the 1 in the numerator of the second ratio. This is because a whole tank is represented by 9/9 which is the same thing as 1.
Cross multiply to solve for x:
To solve for x we will multiply both sides by 9/5:
9/5 and 5/9 cancel each other out when multiplied leaving simply "x" on the left. And multiplying on the right:
which divides to 3.6 minutes